Just a quick and simple question regarding the example.hpp file that encapsulates OpenGL rendering and window management functions.

All I see is:

#define GLFW_INCLUDE_GLU
#include <GLFW/glfw3.h>

#include "../third-party/stb_easy_font.h"

with no

#include <librealsense\rs.hpp>

How is it possible that rs2::frameset& frames or rs2::video_frame& frame can still be compiled and called without any errors? I am just trying to learn more and understand more, any help is much appreciated. Thank you :)